Lateral bipolar sensor with sensing signal amplification

1. An integrated sensor, comprising: a sensing structure; a first bipolar junction transistor having a base that is electrically coupled with the sensing structure, the first bipolar junction transistor being configured to generate an output signal indicative of a change in stored charge in the sensing structure resulting from a presence of an environmental property; and a second bipolar junction transistor, the second bipolar junction transistor being configured to amplify the output signal of the first bipolar junction transistor; wherein the first and second bipolar junction transistors and the sensing structure are monolithically formed on a common substrate; wherein each of said first and second bipolar junction transistors comprises an inverted lateral bipolar junction transistor having an extrinsic base region formed underneath an intrinsic base thereof, the extrinsic base region having a higher doping concentration than the substrate.

2. The sensor of claim 1 , wherein the sensing structure comprises an insulating layer positioned on and contacting an intrinsic base of said first bipolar junction transistor.

3. The sensor of claim 1 , wherein the sensing structure comprises at least one insulating layer and at least one metal layer, the insulating layer being positioned on and contacting an intrinsic base of said first bipolar junction transistor and the metal layer being positioned on an upper surface of the insulating layer.

4. The sensor of claim 1 , wherein the substrate is of a first conductivity type and the extrinsic base region comprises a well of a second conductivity type formed in the substrate, the well having a higher doping concentration than the substrate, and wherein the intrinsic base comprises a region of the second conductivity type formed on at least a portion of the well and being electrically coupled with the well, the intrinsic base having a lower doping concentration than the well.

5. The sensor of claim 4 , wherein the substrate is an n-type substrate, the well is a p+ well, and the intrinsic base comprises a p-type silicon-germanium layer.

6. The sensor of claim 1 , wherein at least the second bipolar junction transistor comprises a heterojunction bipolar transistor.

7. The sensor of claim 1 , wherein a gain of the second bipolar junction transistor is controlled by controlling a doping ratio between an emitter and a base of the second bipolar junction transistor.

8. The sensor of claim 1 , wherein the first and second bipolar junction transistors are laterally adjacent to one another and electrically isolated by a shallow trench isolation region formed therebetween.

9. The sensor of claim 1 , wherein the sensing structure comprises at least one of hafnium oxide (HfO 2 ), tantalum oxide (Ta 2 O 5 ), and a dual-layer silicon dioxide (SiO 2 )/high-dielectric constant film.

10. The sensor of claim 1 , wherein a current generated by an emitter of the first bipolar junction transistor is fed directly into a base of the second bipolar junction transistor, the output signal of the sensor being generated at a collector of the second bipolar junction transistor.

11. A method of forming a sensor for detecting a presence of at least one of an environmental material and an environmental condition, the method comprising steps of: forming a sensing structure on a semiconductor substrate; forming a first bipolar junction transistor on said substrate, the first bipolar junction transistor having a base that is electrically coupled with the sensing structure, the first bipolar junction transistor being configured to generate an output signal indicative of a change in stored charge in the sensing structure resulting from the presence of at least one of said environmental material and said environmental condition; and forming a second bipolar junction transistor on said substrate, the second bipolar junction transistor being configured to amplify the output signal of the first bipolar junction transistor, the first and second bipolar junction transistors being formed adjacent to one another on the substrate; wherein each of said first and second bipolar junction transistors comprises an inverted lateral bipolar junction transistor having an extrinsic base region formed underneath an intrinsic base thereof, the extrinsic base region having a higher doping concentration than the substrate.

12. A method of forming a sensor for detecting a presence of at least one of an environmental material and an environmental condition, the method comprising steps of: forming a sensing structure on a semiconductor substrate; forming a first bipolar junction transistor on said substrate, the first bipolar junction transistor having a base that is electrically coupled with the sensing structure, the first bipolar junction transistor being configured to generate an output signal indicative of a change in stored charge in the sensing structure resulting from the presence of at least one of said environmental material and said environmental condition; and forming a second bipolar junction transistor on said substrate, the second bipolar junction transistor being configured to amplify the output signal of the first bipolar junction transistor, the first and second bipolar junction transistors being formed adjacent to one another on the substrate; wherein forming a given one of said first and second bipolar junction transistors comprises: forming a well of a first conductivity type in the substrate, the substrate being of a second conductivity type, said well forming an extrinsic base; forming a region of the first conductivity type on at least a portion of the well and being electrically coupled with the well, the region of the first conductivity type forming an intrinsic base; forming shallow trench isolation (STI) regions above and at least partially into the underlying well; forming doped polysilicon regions of the second conductivity type in the STI regions proximate an upper surface of the STI regions, the doped polysilicon regions being spaced laterally from one another and being in electrical connection with the intrinsic base, the doped polysilicon regions respectively forming an emitter and a collector of the given one of the first and second bipolar junction transistors.

13. The method of claim 12 , wherein the well is formed having a higher doping concentration than the substrate, and wherein the region of the first conductivity type is formed having a lower doping concentration than the well.

14. The method of claim 11 , wherein forming said sensing structure comprises forming an insulating layer positioned on and contacting an intrinsic base of said first bipolar junction transistor.

15. The method of claim 11 , wherein forming said sensing structure comprises forming at least one insulating layer and at least one metal layer, the insulating layer being positioned on and contacting an intrinsic base of said first bipolar junction transistor and the metal layer being positioned on an upper surface of the insulating layer.

16. The method of claim 11 , further comprising controlling a gain of the second bipolar junction transistor by controlling a doping ratio between an emitter and a base of the second bipolar junction transistor.

17. The method of claim 11 , further comprising configuring said sensing structure for a prescribed sensing application and environment by changing at least one of a material type and dimensions of the sensing structure.

18. The method of claim 11 , further comprising forming a passivation layer on an upper surface of the sensor, the passivation layer having an opening formed above at least a portion of an intrinsic base of the first bipolar junction transistor, at least a portion of said sensing structure being formed in the opening of the passivation layer and electrically coupled with the intrinsic base of the first bipolar junction transistor.